The Applicant's Patent Application DE 10 2014 226 699.8, which is not a prior publication, describes a gearbox having an input shaft, an output shaft, a first planetary gear set which is a stepped planetary gear set and the planetary gears of which have two different effective diameters, and a second planetary gear set, wherein the first and the second planetary gear set are minus gear sets. A first sun gear of the first planetary gear set engages the larger effective diameter of the planetary gears. A second sun gear of the first planetary gear set engages the smaller effective diameter of the planetary gears. The second sun gear of the first planetary gear set is continuously connected to a sun gear of the second planetary gear set. A carrier of the first planetary gear set is continuously connected to a ring gear of the second planetary gear set. The input shaft is connectable via a first shift element to the carrier of the second planetary gear set and via a second shift element to the second sun gear of the first planetary gear set. The output shaft is connected to the ring gear of the second planetary gear set. This gearbox furthermore has an electric machine, wherein the input shaft is connectable to a rotor of the electric machine via a third shift element. The first sun gear of the first planetary gear set is connected to the rotor either continuously or selectively via an additional shift element. A ring gear of the first planetary gear set is rotationally fixedly immobilizable via a fourth shift element.